ARS | Publication request: Field application of serodiagnostics to identify elephants with Tuberculosis prior to case confirmation by culture

Submitted to: Clinical and Vaccine Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 2, 2012
Publication Date: June 27, 2012
Citation: Lyashchenko, K.P., Greenwald, R., Esfandiari, J., Mikota, S., Miller, M., Moller, T., Vogelnest, L., Gairhe, K.P., Robbe-Austerman, S., Gai, J., Waters, W.R. 2012. Field application of serodiagnostics to identify elephants with Tuberculosis prior to case confirmation by culture. Clinical and Vaccine Immunology. 19(8):1269-1275.

Interpretive Summary: Tuberculosis is common in elephants in zoos, circuses, and wildlife parks within the United States. This infection represents a serious risk to elephant handlers, exhibit visitors, and other animals. Two methods are currently recognized to diagnose tuberculosis in elephants: trunk wash culture and a recently developed assay to detect antibodies to the infection. In the present study, confirmation of the validity of the antibody-based test was determined in a prospective study. Findings indicate that the antibody-based test is a much more sensitive measure of the disease. Furthermore, it was determined that evaluation of antibody responses was a reliable method to evaluate the effectiveness of therapy to cure the disease. These findings will be useful for the validation of recent revisions to the guidelines for the surveillance of tuberculosis in elephants.

Technical Abstract: Three serologic methods for antibody detection in elephant tuberculosis (TB), multiantigen print immunoassay (MAPIA), ElephantTB STAT-PAK kit, and DPP VetTB test, were validated prospectively using serial serum samples from 14 captive elephants in 5 countries which were diagnosed with TB by positive culture from trunk wash specimens or from tissues samples collected at postmortem examination. All elephants produced antibody responses to Mycobacterium tuberculosis antigens, with 13/14 recognizing ESAT-6 and/or CFP10 proteins. The findings supported the high serodiagnostic test accuracy in detecting elephant infections months or years before M. tuberculosis could be isolated. Semi-quantitative MAPIA and/or DPP VetTB assay demonstrated the potential for monitoring antibiotic therapy and for predicting TB relapse in treated elephants when continuously used in the post-treatment period. History of exposure to TB and past treatment information should be taken into consideration for better interpretation of the antibody test results. Data suggests that more frequent trunk wash culture testing of the antibody positive suspects may boost the efficiency of elephant TB diagnostic algorithm leading to earlier treatment with improved outcomes.